Method and apparatus to provide telemetry data to a power controller of a processor

ABSTRACT

In an embodiment, a processor includes a plurality of cores including a first core. The first core includes a first plurality of accumulator logics, each accumulator logic of the first plurality of accumulator logics to store corresponding first core telemetry data. The processor also includes a power management unit (PMU) to request telemetry data from the first core and in response to receive the first core telemetry data stored in at least one accumulator logic of the first plurality of accumulator logics. Other embodiments are described and claimed.

TECHNICAL FIELD

Embodiments relate to power management of a system, and moreparticularly to power management of a multicore processor.

BACKGROUND

Advances in semiconductor processing and logic design have permitted anincrease in the amount of logic that may be present on integratedcircuit devices. As a result, computer system configurations haveevolved from a single or multiple integrated circuits in a system tomultiple hardware threads, multiple cores, multiple devices, and/orcomplete systems on individual integrated circuits. Additionally, as thedensity of integrated circuits has grown, the power requirements forcomputing systems (from embedded systems to servers) have alsoescalated. Furthermore, software inefficiencies, and its requirements ofhardware, have also caused an increase in computing device energyconsumption. In fact, some studies indicate that computing devicesconsume a sizeable percentage of the entire electricity supply for acountry, such as the United States of America. As a result, there is avital need for energy efficiency and conservation associated withintegrated circuits. These needs will increase as servers, desktopcomputers, notebooks, Ultrabooks™, tablets, mobile phones, processors,embedded systems, etc. become even more prevalent (from inclusion in thetypical computer, automobiles, and televisions to biotechnology).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a portion of a system in accordance with anembodiment of the present invention.

FIG. 2 is a block diagram of a processor in accordance with anembodiment of the present invention.

FIG. 3 is a block diagram of a multi-domain processor in accordance withanother embodiment of the present invention.

FIG. 4 is an embodiment of a processor including multiple cores.

FIG. 5 is a block diagram of a micro-architecture of a processor core inaccordance with one embodiment of the present invention.

FIG. 6 is a block diagram of a micro-architecture of a processor core inaccordance with another embodiment.

FIG. 7 is a block diagram of a micro-architecture of a processor core inaccordance with yet another embodiment.

FIG. 8 is a block diagram of a micro-architecture of a processor core inaccordance with a still further embodiment.

FIG. 9 is a block diagram of a processor in accordance with anotherembodiment of the present invention.

FIG. 10 is a block diagram of a representative SoC in accordance with anembodiment of the present invention.

FIG. 11 is a block diagram of another example SoC in accordance with anembodiment of the present invention.

FIG. 12 is a block diagram of an example system with which embodimentscan be used.

FIG. 13 is a block diagram of another example system with whichembodiments may be used.

FIG. 14 is a block diagram of a representative computer system.

FIG. 15 is a block diagram of a system in accordance with an embodimentof the present invention.

FIG. 16 is a block diagram of a processor, according to an embodiment ofthe present invention.

FIG. 17 is a block diagram of a processor, according to anotherembodiment of the present invention.

FIG. 18 is a flow diagram of a method, according to an embodiment of thepresent invention.

FIG. 19 is a flow diagram of a method, according to another embodimentof the present invention.

DETAILED DESCRIPTION

Although the following embodiments are described with reference toenergy conservation and energy efficiency in specific integratedcircuits, such as in computing platforms or processors, otherembodiments are applicable to other types of integrated circuits andlogic devices. Similar techniques and teachings of embodiments describedherein may be applied to other types of circuits or semiconductordevices that may also benefit from better energy efficiency and energyconservation. For example, the disclosed embodiments are not limited toany particular type of computer systems. That is, disclosed embodimentscan be used in many different system types, ranging from servercomputers (e.g., tower, rack, blade, micro-server and so forth),communications systems, storage systems, desktop computers of anyconfiguration, laptop, notebook, and tablet computers (including 2:1tablets, phablets and so forth), and may be also used in other devices,such as handheld devices, systems on chip (SoCs), and embeddedapplications. Some examples of handheld devices include cellular phonessuch as smartphones, Internet protocol devices, digital cameras,personal digital assistants (PDAs), and handheld PCs. Embeddedapplications may typically include a microcontroller, a digital signalprocessor (DSP), network computers (NetPC), set-top boxes, network hubs,wide area network (WAN) switches, wearable devices, or any other systemthat can perform the functions and operations taught below. More so,embodiments may be implemented in mobile terminals having standard voicefunctionality such as mobile phones, smartphones and phablets, and/or innon-mobile terminals without a standard wireless voice functioncommunication capability, such as many wearables, tablets, notebooks,desktops, micro-servers, servers and so forth. Moreover, theapparatuses, methods, and systems described herein are not limited tophysical computing devices, but may also relate to softwareoptimizations for energy conservation and efficiency. As will becomereadily apparent in the description below, the embodiments of methods,apparatuses, and systems described herein (whether in reference tohardware, firmware, software, or a combination thereof) are vital to a‘green technology’ future, such as for power conservation and energyefficiency in products that encompass a large portion of the US economy.

Referring now to FIG. 1, shown is a block diagram of a portion of asystem in accordance with an embodiment of the present invention. Asshown in FIG. 1, system 100 may include various components, including aprocessor 110 which as shown is a multicore processor. Processor 110 maybe coupled to a power supply 150 via an external voltage regulator 160,which may perform a first voltage conversion to provide a primaryregulated voltage to processor 110.

As seen, processor 110 may be a single die processor including multiplecores 120 _(a)-120 _(n). In addition, each core may be associated withan integrated voltage regulator (IVR) 125 _(a)-125 _(n) which receivesthe primary regulated voltage and generates an operating voltage to beprovided to one or more agents of the processor associated with the IVR.Accordingly, an IVR implementation may be provided to allow forfine-grained control of voltage and thus power and performance of eachindividual core. As such, each core can operate at an independentvoltage and frequency, enabling great flexibility and affording wideopportunities for balancing power consumption with performance. In someembodiments, the use of multiple IVRs enables the grouping of componentsinto separate power planes, such that power is regulated and supplied bythe IVR to only those components in the group. During power management,a given power plane of one IVR may be powered down or off when theprocessor is placed into a certain low power state, while another powerplane of another IVR remains active, or fully powered.

Still referring to FIG. 1, additional components may be present withinthe processor including an input/output interface 132, another interface134, and an integrated memory controller 136. As seen, each of thesecomponents may be powered by another integrated voltage regulator 125_(x). In one embodiment, interface 132 may be enable operation for anIntel® Quick Path Interconnect (QPI) interconnect, which provides forpoint-to-point (PtP) links in a cache coherent protocol that includesmultiple layers including a physical layer, a link layer and a protocollayer. In turn, interface 134 may communicate via a Peripheral ComponentInterconnect Express (PCIe™) protocol.

Also shown is a power control unit (PCU) 138, which may includehardware, software and/or firmware to perform power managementoperations with regard to processor 110. As seen, PCU 138 providescontrol information to external voltage regulator 160 via a digitalinterface to cause the voltage regulator to generate the appropriateregulated voltage. PCU 138 also provides control information to IVRs 125via another digital interface to control the operating voltage generated(or to cause a corresponding IVR to be disabled in a low power mode). Invarious embodiments, PCU 138 may include a variety of power managementlogic units to perform hardware-based power management. Such powermanagement may be wholly processor controlled (e.g., by variousprocessor hardware, and which may be triggered by workload and/or power,thermal or other processor constraints) and/or the power management maybe performed responsive to external sources (such as a platform ormanagement power management source or system software).

While not shown for ease of illustration, understand that additionalcomponents may be present within processor 110 such as uncore logic, andother components such as internal memories, e.g., one or more levels ofa cache memory hierarchy and so forth. Furthermore, while shown in theimplementation of FIG. 1 with an integrated voltage regulator,embodiments are not so limited.

Note that the power management techniques described herein may beindependent of and complementary to an operating system (OS)-based powermanagement (OSPM) mechanism. According to one example OSPM technique, aprocessor can operate at various performance states or levels, so-calledP-states, namely from P0 to PN. In general, the P1 performance state maycorrespond to the highest guaranteed performance state that can berequested by an OS. In addition to this P1 state, the OS can furtherrequest a higher performance state, namely a P0 state. This P0 state maythus be an opportunistic or turbo mode state in which, when power and/orthermal budget is available, processor hardware can configure theprocessor or at least portions thereof to operate at a higher thanguaranteed frequency. In many implementations a processor can includemultiple so-called bin frequencies above the P1 guaranteed maximumfrequency, exceeding to a maximum peak frequency of the particularprocessor, as fused or otherwise written into the processor duringmanufacture. In addition, according to one OSPM mechanism, a processorcan operate at various power states or levels. With regard to powerstates, an OSPM mechanism may specify different power consumptionstates, generally referred to as C-states, C0, C1 to Cn states. When acore is active, it runs at a C0 state, and when the core is idle it maybe placed in a core low power state, also called a core non-zero C-state(e.g., C1-C6 states), with each C-state being at a lower powerconsumption level (such that C6 is a deeper low power state than C1, andso forth).

Understand that many different types of power management techniques maybe used individually or in combination in different embodiments. Asrepresentative examples, a power controller may control the processor tobe power managed by some form of dynamic voltage frequency scaling(DVFS) in which an operating voltage and/or operating frequency of oneor more cores or other processor logic may be dynamically controlled toreduce power consumption in certain situations. In an example, DVFS maybe performed using Enhanced Intel SpeedStep™ technology available fromIntel Corporation, Santa Clara, Calif., to provide optimal performanceat a lowest power consumption level. In another example, DVFS may beperformed using Intel TurboBoost™ technology to enable one or more coresor other compute engines to operate at a higher than guaranteedoperating frequency based on conditions (e.g., workload andavailability).

Another power management technique that may be used in certain examplesis dynamic swapping of workloads between different compute engines. Forexample, the processor may include asymmetric cores or other processingengines that operate at different power consumption levels, such that ina power constrained situation, one or more workloads can be dynamicallyswitched to execute on a lower power core or other compute engine.Another exemplary power management technique is hardware duty cycling(HDC), which may cause cores and/or other compute engines to beperiodically enabled and disabled according to a duty cycle, such thatone or more cores may be made inactive during an inactive period of theduty cycle and made active during an active period of the duty cycle.Although described with these particular examples, understand that manyother power management techniques may be used in particular embodiments.

Embodiments can be implemented in processors for various marketsincluding server processors, desktop processors, mobile processors andso forth. Referring now to FIG. 2, shown is a block diagram of aprocessor in accordance with an embodiment of the present invention. Asshown in FIG. 2, processor 200 may be a multicore processor including aplurality of cores 210 _(a)-210 _(n). In one embodiment, each such coremay be of an independent power domain and can be configured to enter andexit active states and/or maximum performance states based on workload.The various cores may be coupled via an interconnect 215 to a systemagent or uncore 220 that includes various components. As seen, theuncore 220 may include a shared cache 230 which may be a last levelcache. In addition, the uncore may include an integrated memorycontroller 240 to communicate with a system memory (not shown in FIG.2), e.g., via a memory bus. Uncore 220 also includes various interfaces250 and a power control unit 255, which may include logic to perform thepower management techniques described herein.

In addition, by interfaces 250 a-250 n, connection can be made tovarious off-chip components such as peripheral devices, mass storage andso forth. While shown with this particular implementation in theembodiment of FIG. 2, the scope of the present invention is not limitedin this regard.

Referring now to FIG. 3, shown is a block diagram of a multi-domainprocessor in accordance with another embodiment of the presentinvention. As shown in the embodiment of FIG. 3, processor 300 includesmultiple domains. Specifically, a core domain 310 can include aplurality of cores 310 ₀-310 _(n), a graphics domain 320 can include oneor more graphics engines, and a system agent domain 350 may further bepresent. In some embodiments, system agent domain 350 may execute at anindependent frequency than the core domain and may remain powered on atall times to handle power control events and power management such thatdomains 310 and 320 can be controlled to dynamically enter into and exithigh power and low power states. Each of domains 310 and 320 may operateat different voltage and/or power. Note that while only shown with threedomains, understand the scope of the present invention is not limited inthis regard and additional domains can be present in other embodiments.For example, multiple core domains may be present each including atleast one core.

In general, each core 310 may further include low level caches inaddition to various execution units and additional processing elements.In turn, the various cores may be coupled to each other and to a sharedcache memory formed of a plurality of units of a last level cache (LLC)340 ₀-340 _(n). In various embodiments, LLC 340 may be shared amongstthe cores and the graphics engine, as well as various media processingcircuitry. As seen, a ring interconnect 330 thus couples the corestogether, and provides interconnection between the cores, graphicsdomain 320 and system agent circuitry 350. In one embodiment,interconnect 330 can be part of the core domain. However in otherembodiments the ring interconnect can be of its own domain.

As further seen, system agent domain 350 may include display controller352 which may provide control of and an interface to an associateddisplay. As further seen, system agent domain 350 may include a powercontrol unit 355 which can include logic to perform the power managementtechniques described herein.

As further seen in FIG. 3, processor 300 can further include anintegrated memory controller (IMC) 370 that can provide for an interfaceto a system memory, such as a dynamic random access memory (DRAM).Multiple interfaces 380 ₀-380 _(n) may be present to enableinterconnection between the processor and other circuitry. For example,in one embodiment at least one direct media interface (DMI) interfacemay be provided as well as one or more PCIe™ interfaces. Still further,to provide for communications between other agents such as additionalprocessors or other circuitry, one or more QPI interfaces may also beprovided. Although shown at this high level in the embodiment of FIG. 3,understand the scope of the present invention is not limited in thisregard.

Referring to FIG. 4, an embodiment of a processor including multiplecores is illustrated. Processor 400 includes any processor or processingdevice, such as a microprocessor, an embedded processor, a digitalsignal processor (DSP), a network processor, a handheld processor, anapplication processor, a co-processor, a system on a chip (SoC), orother device to execute code. Processor 400, in one embodiment, includesat least two cores—cores 401 and 402, which may include asymmetric coresor symmetric cores (the illustrated embodiment). However, processor 400may include any number of processing elements that may be symmetric orasymmetric.

In one embodiment, a processing element refers to hardware or logic tosupport a software thread. Examples of hardware processing elementsinclude: a thread unit, a thread slot, a thread, a process unit, acontext, a context unit, a logical processor, a hardware thread, a core,and/or any other element, which is capable of holding a state for aprocessor, such as an execution state or architectural state. In otherwords, a processing element, in one embodiment, refers to any hardwarecapable of being independently associated with code, such as a softwarethread, operating system, application, or other code. A physicalprocessor typically refers to an integrated circuit, which potentiallyincludes any number of other processing elements, such as cores orhardware threads.

A core often refers to logic located on an integrated circuit capable ofmaintaining an independent architectural state, wherein eachindependently maintained architectural state is associated with at leastsome dedicated execution resources. In contrast to cores, a hardwarethread typically refers to any logic located on an integrated circuitcapable of maintaining an independent architectural state, wherein theindependently maintained architectural states share access to executionresources. As can be seen, when certain resources are shared and othersare dedicated to an architectural state, the line between thenomenclature of a hardware thread and core overlaps. Yet often, a coreand a hardware thread are viewed by an operating system as individuallogical processors, where the operating system is able to individuallyschedule operations on each logical processor.

Physical processor 400, as illustrated in FIG. 4, includes two cores,cores 401 and 402. Here, cores 401 and 402 are considered symmetriccores, i.e., cores with the same configurations, functional units,and/or logic. In another embodiment, core 401 includes an out-of-orderprocessor core, while core 402 includes an in-order processor core.However, cores 401 and 402 may be individually selected from any type ofcore, such as a native core, a software managed core, a core adapted toexecute a native instruction set architecture (ISA), a core adapted toexecute a translated ISA, a co-designed core, or other known core. Yetto further the discussion, the functional units illustrated in core 401are described in further detail below, as the units in core 402 operatein a similar manner.

As depicted, core 401 includes two hardware threads 401 a and 401 b,which may also be referred to as hardware thread slots 401 a and 401 b.Therefore, software entities, such as an operating system, in oneembodiment potentially view processor 400 as four separate processors,i.e., four logical processors or processing elements capable ofexecuting four software threads concurrently. As alluded to above, afirst thread is associated with architecture state registers 401 a, asecond thread is associated with architecture state registers 401 b, athird thread may be associated with architecture state registers 402 a,and a fourth thread may be associated with architecture state registers402 b. Here, each of the architecture state registers (401 a, 401 b, 402a, and 402 b) may be referred to as processing elements, thread slots,or thread units, as described above. As illustrated, architecture stateregisters 401 a are replicated in architecture state registers 401 b, soindividual architecture states/contexts are capable of being stored forlogical processor 401 a and logical processor 401 b. In core 401, othersmaller resources, such as instruction pointers and renaming logic inallocator and renamer block 430 may also be replicated for threads 401 aand 401 b. Some resources, such as re-order buffers inreorder/retirement unit 435, ILTB 420, load/store buffers, and queuesmay be shared through partitioning. Other resources, such as generalpurpose internal registers, page-table base register(s), low-leveldata-cache and data-TLB 415, execution unit(s) 440, and portions ofout-of-order unit 435 are potentially fully shared.

Processor 400 often includes other resources, which may be fully shared,shared through partitioning, or dedicated by/to processing elements. InFIG. 4, an embodiment of a purely exemplary processor with illustrativelogical units/resources of a processor is illustrated. Note that aprocessor may include, or omit, any of these functional units, as wellas include any other known functional units, logic, or firmware notdepicted. As illustrated, core 401 includes a simplified, representativeout-of-order (OOO) processor core. But an in-order processor may beutilized in different embodiments. The OOO core includes a branch targetbuffer 420 to predict branches to be executed/taken and aninstruction-translation buffer (I-TLB) 420 to store address translationentries for instructions.

Core 401 further includes decode module 425 coupled to fetch unit 420 todecode fetched elements. Fetch logic, in one embodiment, includesindividual sequencers associated with thread slots 401 a, 401 b,respectively. Usually core 401 is associated with a first ISA, whichdefines/specifies instructions executable on processor 400. Oftenmachine code instructions that are part of the first ISA include aportion of the instruction (referred to as an opcode), whichreferences/specifies an instruction or operation to be performed. Decodelogic 425 includes circuitry that recognizes these instructions fromtheir opcodes and passes the decoded instructions on in the pipeline forprocessing as defined by the first ISA. For example, decoders 425, inone embodiment, include logic designed or adapted to recognize specificinstructions, such as transactional instruction. As a result of therecognition by decoders 425, the architecture or core 401 takesspecific, predefined actions to perform tasks associated with theappropriate instruction. It is important to note that any of the tasks,blocks, operations, and methods described herein may be performed inresponse to a single or multiple instructions; some of which may be newor old instructions.

In one example, allocator and renamer block 430 includes an allocator toreserve resources, such as register files to store instructionprocessing results. However, threads 401 a and 401 b are potentiallycapable of out-of-order execution, where allocator and renamer block 430also reserves other resources, such as reorder buffers to trackinstruction results. Unit 430 may also include a register renamer torename program/instruction reference registers to other registersinternal to processor 400. Reorder/retirement unit 435 includescomponents, such as the reorder buffers mentioned above, load buffers,and store buffers, to support out-of-order execution and later in-orderretirement of instructions executed out-of-order.

Scheduler and execution unit(s) block 440, in one embodiment, includes ascheduler unit to schedule instructions/operation on execution units.For example, a floating point instruction is scheduled on a port of anexecution unit that has an available floating point execution unit.Register files associated with the execution units are also included tostore information instruction processing results. Exemplary executionunits include a floating point execution unit, an integer executionunit, a jump execution unit, a load execution unit, a store executionunit, and other known execution units.

Lower level data cache and data translation buffer (D-TLB) 450 arecoupled to execution unit(s) 440. The data cache is to store recentlyused/operated on elements, such as data operands, which are potentiallyheld in memory coherency states. The D-TLB is to store recentvirtual/linear to physical address translations. As a specific example,a processor may include a page table structure to break physical memoryinto a plurality of virtual pages.

Here, cores 401 and 402 share access to higher-level or further-outcache 410, which is to cache recently fetched elements. Note thathigher-level or further-out refers to cache levels increasing or gettingfurther away from the execution unit(s). In one embodiment, higher-levelcache 410 is a last-level data cache—last cache in the memory hierarchyon processor 400—such as a second or third level data cache. However,higher level cache 410 is not so limited, as it may be associated withor includes an instruction cache. A trace cache—a type of instructioncache—instead may be coupled after decoder 425 to store recently decodedtraces.

In the depicted configuration, processor 400 also includes bus interfacemodule 405 and a power controller 460, which may perform powermanagement in accordance with an embodiment of the present invention. Inthis scenario, bus interface 405 is to communicate with devices externalto processor 400, such as system memory and other components.

A memory controller 470 may interface with other devices such as one ormany memories. In an example, bus interface 405 includes a ringinterconnect with a memory controller for interfacing with a memory anda graphics controller for interfacing with a graphics processor. In anSoC environment, even more devices, such as a network interface,coprocessors, memory, graphics processor, and any other known computerdevices/interface may be integrated on a single die or integratedcircuit to provide small form factor with high functionality and lowpower consumption.

Referring now to FIG. 5, shown is a block diagram of amicro-architecture of a processor core in accordance with one embodimentof the present invention. As shown in FIG. 5, processor core 500 may bea multi-stage pipelined out-of-order processor. Core 500 may operate atvarious voltages based on a received operating voltage, which may bereceived from an integrated voltage regulator or external voltageregulator.

As seen in FIG. 5, core 500 includes front end units 510, which may beused to fetch instructions to be executed and prepare them for use laterin the processor pipeline. For example, front end units 510 may includea fetch unit 501, an instruction cache 503, and an instruction decoder505. In some implementations, front end units 510 may further include atrace cache, along with microcode storage as well as a micro-operationstorage. Fetch unit 501 may fetch macro-instructions, e.g., from memoryor instruction cache 503, and feed them to instruction decoder 505 todecode them into primitives, i.e., micro-operations for execution by theprocessor.

Coupled between front end units 510 and execution units 520 is anout-of-order (OOO) engine 515 that may be used to receive themicro-instructions and prepare them for execution. More specifically OOOengine 515 may include various buffers to re-order micro-instructionflow and allocate various resources needed for execution, as well as toprovide renaming of logical registers onto storage locations withinvarious register files such as register file 530 and extended registerfile 535. Register file 530 may include separate register files forinteger and floating point operations. For purposes of configuration,control, and additional operations, a set of machine specific registers(MSRs) 538 may also be present and accessible to various logic withincore 500 (and external to the core). For example, power limitinformation may be stored in one or more MSR and be dynamically updatedas described herein.

Various resources may be present in execution units 520, including, forexample, various integer, floating point, and single instructionmultiple data (SIMD) logic units, among other specialized hardware. Forexample, such execution units may include one or more arithmetic logicunits (ALUs) 522 and one or more vector execution units 524, among othersuch execution units.

Results from the execution units may be provided to retirement logic,namely a reorder buffer (ROB) 540. More specifically, ROB 540 mayinclude various arrays and logic to receive information associated withinstructions that are executed. This information is then examined by ROB540 to determine whether the instructions can be validly retired andresult data committed to the architectural state of the processor, orwhether one or more exceptions occurred that prevent a proper retirementof the instructions. Of course, ROB 540 may handle other operationsassociated with retirement.

As shown in FIG. 5, ROB 540 is coupled to a cache 550 which, in oneembodiment may be a low level cache (e.g., an L1 cache) although thescope of the present invention is not limited in this regard. Also,execution units 520 can be directly coupled to cache 550. From cache550, data communication may occur with higher level caches, systemmemory and so forth. While shown with this high level in the embodimentof FIG. 5, understand the scope of the present invention is not limitedin this regard. For example, while the implementation of FIG. 5 is withregard to an out-of-order machine such as of an Intel® x86 instructionset architecture (ISA), the scope of the present invention is notlimited in this regard. That is, other embodiments may be implemented inan in-order processor, a reduced instruction set computing (RISC)processor such as an ARM-based processor, or a processor of another typeof ISA that can emulate instructions and operations of a different ISAvia an emulation engine and associated logic circuitry.

Referring now to FIG. 6, shown is a block diagram of amicro-architecture of a processor core in accordance with anotherembodiment. In the embodiment of FIG. 6, core 600 may be a low powercore of a different micro-architecture, such as an Intel® Atom™-basedprocessor having a relatively limited pipeline depth designed to reducepower consumption. As seen, core 600 includes an instruction cache 610coupled to provide instructions to an instruction decoder 615. A branchpredictor 605 may be coupled to instruction cache 610. Note thatinstruction cache 610 may further be coupled to another level of a cachememory, such as an L2 cache (not shown for ease of illustration in FIG.6). In turn, instruction decoder 615 provides decoded instructions to anissue queue 620 for storage and delivery to a given execution pipeline.A microcode ROM 618 is coupled to instruction decoder 615.

A floating point pipeline 630 includes a floating point register file632 which may include a plurality of architectural registers of a givenbit with such as 128, 256 or 512 bits. Pipeline 630 includes a floatingpoint scheduler 634 to schedule instructions for execution on one ofmultiple execution units of the pipeline. In the embodiment shown, suchexecution units include an ALU 635, a shuffle unit 636, and a floatingpoint adder 638. In turn, results generated in these execution units maybe provided back to buffers and/or registers of register file 632. Ofcourse understand while shown with these few example execution units,additional or different floating point execution units may be present inanother embodiment.

An integer pipeline 640 also may be provided. In the embodiment shown,pipeline 640 includes an integer register file 642 which may include aplurality of architectural registers of a given bit with such as 128 or256 bits. Pipeline 640 includes an integer scheduler 644 to scheduleinstructions for execution on one of multiple execution units of thepipeline. In the embodiment shown, such execution units include an ALU645, a shifter unit 646, and a jump execution unit 648. In turn, resultsgenerated in these execution units may be provided back to buffersand/or registers of register file 642. Of course understand while shownwith these few example execution units, additional or different integerexecution units may be present in another embodiment.

A memory execution scheduler 650 may schedule memory operations forexecution in an address generation unit 652, which is also coupled to aTLB 654. As seen, these structures may couple to a data cache 660, whichmay be a L0 and/or L1 data cache that in turn couples to additionallevels of a cache memory hierarchy, including an L2 cache memory.

To provide support for out-of-order execution, an allocator/renamer 670may be provided, in addition to a reorder buffer 680, which isconfigured to reorder instructions executed out of order for retirementin order. Although shown with this particular pipeline architecture inthe illustration of FIG. 6, understand that many variations andalternatives are possible.

Note that in a processor having asymmetric cores, such as in accordancewith the micro-architectures of FIGS. 5 and 6, workloads may bedynamically swapped between the cores for power management reasons, asthese cores, although having different pipeline designs and depths, maybe of the same or related ISA. Such dynamic core swapping may beperformed in a manner transparent to a user application (and possiblykernel also).

Referring to FIG. 7, shown is a block diagram of a micro-architecture ofa processor core in accordance with yet another embodiment. Asillustrated in FIG. 7, a core 700 may include a multi-staged in-orderpipeline to execute at very low power consumption levels. As one suchexample, processor 700 may have a micro-architecture in accordance withan ARM Cortex A53 design available from ARM Holdings, LTD., Sunnyvale,Calif. In an implementation, an 8-stage pipeline may be provided that isconfigured to execute both 32-bit and 64-bit code. Core 700 includes afetch unit 710 that is configured to fetch instructions and provide themto a decode unit 715, which may decode the instructions, e.g.,macro-instructions of a given ISA such as an ARMv8 ISA. Note furtherthat a queue 730 may couple to decode unit 715 to store decodedinstructions. Decoded instructions are provided to an issue logic 725,where the decoded instructions may be issued to a given one of multipleexecution units.

With further reference to FIG. 7, issue logic 725 may issue instructionsto one of multiple execution units. In the embodiment shown, theseexecution units include an integer unit 735, a multiply unit 740, afloating point/vector unit 750, a dual issue unit 760, and a load/storeunit 770. The results of these different execution units may be providedto a writeback unit 780. Understand that while a single writeback unitis shown for ease of illustration, in some implementations separatewriteback units may be associated with each of the execution units.Furthermore, understand that while each of the units and logic shown inFIG. 7 is represented at a high level, a particular implementation mayinclude more or different structures. A processor designed using one ormore cores having a pipeline as in FIG. 7 may be implemented in manydifferent end products, extending from mobile devices to server systems.

Referring to FIG. 8, shown is a block diagram of a micro-architecture ofa processor core in accordance with a still further embodiment. Asillustrated in FIG. 8, a core 800 may include a multi-stage multi-issueout-of-order pipeline to execute at very high performance levels (whichmay occur at higher power consumption levels than core 700 of FIG. 7).As one such example, processor 800 may have a microarchitecture inaccordance with an ARM Cortex A57 design. In an implementation, a 15 (orgreater)-stage pipeline may be provided that is configured to executeboth 32-bit and 64-bit code. In addition, the pipeline may provide for 3(or greater)-wide and 3 (or greater)-issue operation. Core 800 includesa fetch unit 810 that is configured to fetch instructions and providethem to a decoder/renamer/dispatcher 815, which may decode theinstructions, e.g., macro-instructions of an ARMv8 instruction setarchitecture, rename register references within the instructions, anddispatch the instructions (eventually) to a selected execution unit.Decoded instructions may be stored in a queue 825. Note that while asingle queue structure is shown for ease of illustration in FIG. 8,understand that separate queues may be provided for each of the multipledifferent types of execution units.

Also shown in FIG. 8 is an issue logic 830 from which decodedinstructions stored in queue 825 may be issued to a selected executionunit. Issue logic 830 also may be implemented in a particular embodimentwith a separate issue logic for each of the multiple different types ofexecution units to which issue logic 830 couples.

Decoded instructions may be issued to a given one of multiple executionunits. In the embodiment shown, these execution units include one ormore integer units 835, a multiply unit 840, a floating point/vectorunit 850, a branch unit 860, and a load/store unit 870. In anembodiment, floating point/vector unit 850 may be configured to handleSIMD or vector data of 128 or 256 bits. Still further, floatingpoint/vector execution unit 850 may perform IEEE-754 double precisionfloating-point operations. The results of these different executionunits may be provided to a writeback unit 880. Note that in someimplementations separate writeback units may be associated with each ofthe execution units. Furthermore, understand that while each of theunits and logic shown in FIG. 8 is represented at a high level, aparticular implementation may include more or different structures.

Note that in a processor having asymmetric cores, such as in accordancewith the micro-architectures of FIGS. 7 and 8, workloads may bedynamically swapped for power management reasons, as these cores,although having different pipeline designs and depths, may be of thesame or related ISA. Such dynamic core swapping may be performed in amanner transparent to a user application (and possibly kernel also).

A processor designed using one or more cores having pipelines as in anyone or more of FIGS. 5-8 may be implemented in many different endproducts, extending from mobile devices to server systems. Referring nowto FIG. 9, shown is a block diagram of a processor in accordance withanother embodiment of the present invention. In the embodiment of FIG.9, processor 900 may be a SoC including multiple domains, each of whichmay be controlled to operate at an independent operating voltage andoperating frequency. As a specific illustrative example, processor 900may be an Intel® Architecture Core™-based processor such as an i3, i5,i7 or another such processor available from Intel Corporation. However,other low power processors such as available from Advanced MicroDevices, Inc. (AMD) of Sunnyvale, Calif., an ARM-based design from ARMHoldings, Ltd. or licensee thereof or a MIPS-based design from MIPSTechnologies, Inc. of Sunnyvale, Calif., or their licensees or adoptersmay instead be present in other embodiments such as an Apple A7processor, a Qualcomm Snapdragon processor, or Texas Instruments OMAPprocessor. Such SoC may be used in a low power system such as asmartphone, tablet computer, phablet computer, Ultrabook™ computer orother portable computing device.

In the high level view shown in FIG. 9, processor 900 includes aplurality of core units 910 ₀-910 _(n). Each core unit may include oneor more processor cores, one or more cache memories and other circuitry.Each core unit 910 may support one or more instructions sets (e.g., anx86 instruction set (with some extensions that have been added withnewer versions); a MIPS instruction set; an ARM instruction set (withoptional additional extensions such as NEON)) or other instruction setor combinations thereof. Note that some of the core units may beheterogeneous resources (e.g., of a different design). In addition, eachsuch core may be coupled to a cache memory (not shown) which in anembodiment may be a shared level (L2) cache memory. A non-volatilestorage 930 may be used to store various program and other data. Forexample, this storage may be used to store at least portions ofmicrocode, boot information such as a BIOS, other system software or soforth.

Each core unit 910 may also include an interface such as a bus interfaceunit to enable interconnection to additional circuitry of the processor.In an embodiment, each core unit 910 couples to a coherent fabric thatmay act as a primary cache coherent on-die interconnect that in turncouples to a memory controller 935. In turn, memory controller 935controls communications with a memory such as a DRAM (not shown for easeof illustration in FIG. 9).

In addition to core units, additional processing engines are presentwithin the processor, including at least one graphics unit 920 which mayinclude one or more graphics processing units (GPUs) to perform graphicsprocessing as well as to possibly execute general purpose operations onthe graphics processor (so-called GPGPU operation). In addition, atleast one image signal processor 925 may be present. Signal processor925 may be configured to process incoming image data received from oneor more capture devices, either internal to the SoC or off-chip.

Other accelerators also may be present. In the illustration of FIG. 9, avideo coder 950 may perform coding operations including encoding anddecoding for video information, e.g., providing hardware accelerationsupport for high definition video content. A display controller 955further may be provided to accelerate display operations includingproviding support for internal and external displays of a system. Inaddition, a security processor 945 may be present to perform securityoperations such as secure boot operations, various cryptographyoperations and so forth.

Each of the units may have its power consumption controlled via a powermanager 940, which may include control logic to perform the variouspower management techniques described herein.

In some embodiments, SoC 900 may further include a non-coherent fabriccoupled to the coherent fabric to which various peripheral devices maycouple. One or more interfaces 960 a-960 d enable communication with oneor more off-chip devices. Such communications may be via a variety ofcommunication protocols such as PCIe™, GPIO, USB, I²C, UART, MIPI, SDIO,DDR, SPI, HDMI, among other types of communication protocols. Althoughshown at this high level in the embodiment of FIG. 9, understand thescope of the present invention is not limited in this regard.

Referring now to FIG. 10, shown is a block diagram of a representativeSoC. In the embodiment shown, SoC 1000 may be a multi-core SoCconfigured for low power operation to be optimized for incorporationinto a smartphone or other low power device such as a tablet computer orother portable computing device. As an example, SoC 1000 may beimplemented using asymmetric or different types of cores, such ascombinations of higher power and/or low power cores, e.g., out-of-ordercores and in-order cores. In different embodiments, these cores may bebased on an Intel® Architecture™ core design or an ARM architecturedesign. In yet other embodiments, a mix of Intel and ARM cores may beimplemented in a given SoC.

As seen in FIG. 10, SoC 1000 includes a first core domain 1010 having aplurality of first cores 1012 ₀-1012 ₃. In an example, these cores maybe low power cores such as in-order cores. In one embodiment these firstcores may be implemented as ARM Cortex A53 cores. In turn, these corescouple to a cache memory 1015 of core domain 1010. In addition, SoC 1000includes a second core domain 1020. In the illustration of FIG. 10,second core domain 1020 has a plurality of second cores 1022 ₀-1022 ₃.In an example, these cores may be higher power-consuming cores thanfirst cores 1012. In an embodiment, the second cores may be out-of-ordercores, which may be implemented as ARM Cortex A57 cores. In turn, thesecores couple to a cache memory 1025 of core domain 1020. Note that whilethe example shown in FIG. 10 includes 4 cores in each domain, understandthat more or fewer cores may be present in a given domain in otherexamples.

With further reference to FIG. 10, a graphics domain 1030 also isprovided, which may include one or more graphics processing units (GPUs)configured to independently execute graphics workloads, e.g., providedby one or more cores of core domains 1010 and 1020. As an example, GPUdomain 1030 may be used to provide display support for a variety ofscreen sizes, in addition to providing graphics and display renderingoperations.

As seen, the various domains couple to a coherent interconnect 1040,which in an embodiment may be a cache coherent interconnect fabric thatin turn couples to an integrated memory controller 1050. Coherentinterconnect 1040 may include a shared cache memory, such as an L3cache, in some examples. In an embodiment, memory controller 1050 may bea direct memory controller to provide for multiple channels ofcommunication with an off-chip memory, such as multiple channels of aDRAM (not shown for ease of illustration in FIG. 10).

In different examples, the number of the core domains may vary. Forexample, for a low power SoC suitable for incorporation into a mobilecomputing device, a limited number of core domains such as shown in FIG.10 may be present. Still further, in such low power SoCs, core domain1020 including higher power cores may have fewer numbers of such cores.For example, in one implementation two cores 1022 may be provided toenable operation at reduced power consumption levels. In addition, thedifferent core domains may also be coupled to an interrupt controller toenable dynamic swapping of workloads between the different domains.

In yet other embodiments, a greater number of core domains, as well asadditional optional IP logic may be present, in that an SoC can bescaled to higher performance (and power) levels for incorporation intoother computing devices, such as desktops, servers, high performancecomputing systems, base stations forth. As one such example, 4 coredomains each having a given number of out-of-order cores may beprovided. Still further, in addition to optional GPU support (which asan example may take the form of a GPGPU), one or more accelerators toprovide optimized hardware support for particular functions (e.g. webserving, network processing, switching or so forth) also may beprovided. In addition, an input/output interface may be present tocouple such accelerators to off-chip components.

Referring now to FIG. 11, shown is a block diagram of another exampleSoC. In the embodiment of FIG. 11, SoC 1100 may include variouscircuitry to enable high performance for multimedia applications,communications and other functions. As such, SoC 1100 is suitable forincorporation into a wide variety of portable and other devices, such assmartphones, tablet computers, smart TVs and so forth. In the exampleshown, SoC 1100 includes a central processor unit (CPU) domain 1110. Inan embodiment, a plurality of individual processor cores may be presentin CPU domain 1110. As one example, CPU domain 1110 may be a quad coreprocessor having 4 multithreaded cores. Such processors may behomogeneous or heterogeneous processors, e.g., a mix of low power andhigh power processor cores.

In turn, a GPU domain 1120 is provided to perform advanced graphicsprocessing in one or more GPUs to handle graphics and compute APIs. ADSP unit 1130 may provide one or more low power DSPs for handlinglow-power multimedia applications such as music playback, audio/videoand so forth, in addition to advanced calculations that may occur duringexecution of multimedia instructions. In turn, a communication unit 1140may include various components to provide connectivity via variouswireless protocols, such as cellular communications (including 3G/4GLTE), wireless local area protocols such as Bluetooth™, IEEE 802.11, andso forth.

Still further, a multimedia processor 1150 may be used to performcapture and playback of high definition video and audio content,including processing of user gestures. A sensor unit 1160 may include aplurality of sensors and/or a sensor controller to interface to variousoff-chip sensors present in a given platform. An image signal processor1170 may be provided with one or more separate ISPs to perform imageprocessing with regard to captured content from one or more cameras of aplatform, including still and video cameras.

A display processor 1180 may provide support for connection to a highdefinition display of a given pixel density, including the ability towirelessly communicate content for playback on such display. Stillfurther, a location unit 1190 may include a GPS receiver with supportfor multiple GPS constellations to provide applications highly accuratepositioning information obtained using as such GPS receiver. Understandthat while shown with this particular set of components in the exampleof FIG. 11, many variations and alternatives are possible.

Referring now to FIG. 12, shown is a block diagram of an example systemwith which embodiments can be used. As seen, system 1200 may be asmartphone or other wireless communicator. A baseband processor 1205 isconfigured to perform various signal processing with regard tocommunication signals to be transmitted from or received by the system.In turn, baseband processor 1205 is coupled to an application processor1210, which may be a main CPU of the system to execute an OS and othersystem software, in addition to user applications such as manywell-known social media and multimedia apps. Application processor 1210may further be configured to perform a variety of other computingoperations for the device.

In turn, application processor 1210 can couple to a userinterface/display 1220, e.g., a touch screen display. In addition,application processor 1210 may couple to a memory system including anon-volatile memory, namely a flash memory 1230 and a system memory,namely a dynamic random access memory (DRAM) 1235. As further seen,application processor 1210 further couples to a capture device 1240 suchas one or more image capture devices that can record video and/or stillimages.

Still referring to FIG. 12, a universal integrated circuit card (UICC)1240 comprising a subscriber identity module and possibly a securestorage and cryptoprocessor is also coupled to application processor1210. System 1200 may further include a security processor 1250 that maycouple to application processor 1210. A plurality of sensors 1225 maycouple to application processor 1210 to enable input of a variety ofsensed information such as accelerometer and other environmentalinformation. An audio output device 1295 may provide an interface tooutput sound, e.g., in the form of voice communications, played orstreaming audio data and so forth.

As further illustrated, a near field communication (NFC) contactlessinterface 1260 is provided that communicates in a NFC near field via anNFC antenna 1265. While separate antennae are shown in FIG. 12,understand that in some implementations one antenna or a different setof antennae may be provided to enable various wireless functionality.

A power management integrated circuit (PMIC) 1215 couples to applicationprocessor 1210 to perform platform level power management. To this end,PMIC 1215 may issue power management requests to application processor1210 to enter certain low power states as desired. Furthermore, based onplatform constraints, PMIC 1215 may also control the power level ofother components of system 1200.

To enable communications to be transmitted and received, variouscircuitry may be coupled between baseband processor 1205 and an antenna1290. Specifically, a radio frequency (RF) transceiver 1270 and awireless local area network (WLAN) transceiver 1275 may be present. Ingeneral, RF transceiver 1270 may be used to receive and transmitwireless data and calls according to a given wireless communicationprotocol such as 3G or 4G wireless communication protocol such as inaccordance with a code division multiple access (CDMA), global systemfor mobile communication (GSM), long term evolution (LTE) or otherprotocol. In addition a GPS sensor 1280 may be present. Other wirelesscommunications such as receipt or transmission of radio signals, e.g.,AM/FM and other signals may also be provided. In addition, via WLANtransceiver 1275, local wireless communications can also be realized.

Referring now to FIG. 13, shown is a block diagram of another examplesystem with which embodiments may be used. In the illustration of FIG.13, system 1300 may be mobile low-power system such as a tabletcomputer, 2:1 tablet, phablet or other convertible or standalone tabletsystem. As illustrated, a SoC 1310 is present and may be configured tooperate as an application processor for the device.

A variety of devices may couple to SoC 1310. In the illustration shown,a memory subsystem includes a flash memory 1340 and a DRAM 1345 coupledto SoC 1310. In addition, a touch panel 1320 is coupled to the SoC 1310to provide display capability and user input via touch, includingprovision of a virtual keyboard on a display of touch panel 1320. Toprovide wired network connectivity, SoC 1310 couples to an Ethernetinterface 1330. A peripheral hub 1325 is coupled to SoC 1310 to enableinterfacing with various peripheral devices, such as may be coupled tosystem 1300 by any of various ports or other connectors.

In addition to internal power management circuitry and functionalitywithin SoC 1310, a PMIC 1380 is coupled to SoC 1310 to provideplatform-based power management, e.g., based on whether the system ispowered by a battery 1390 or AC power via an AC adapter 1395. Inaddition to this power source-based power management, PMIC 1380 mayfurther perform platform power management activities based onenvironmental and usage conditions. Still further, PMIC 1380 maycommunicate control and status information to SoC 1310 to cause variouspower management actions within SoC 1310.

Still referring to FIG. 13, to provide for wireless capabilities, a WLANunit 1350 is coupled to SoC 1310 and in turn to an antenna 1355. Invarious implementations, WLAN unit 1350 may provide for communicationaccording to one or more wireless protocols.

As further illustrated, a plurality of sensors 1360 may couple to SoC1310. These sensors may include various accelerometer, environmental andother sensors, including user gesture sensors. Finally, an audio codec1365 is coupled to SoC 1310 to provide an interface to an audio outputdevice 1370. Of course understand that while shown with this particularimplementation in FIG. 13, many variations and alternatives arepossible.

Referring now to FIG. 14, shown is a block diagram of a representativecomputer system such as notebook, Ultrabook™ or other small form factorsystem. A processor 1410, in one embodiment, includes a microprocessor,multi-core processor, multithreaded processor, an ultra low voltageprocessor, an embedded processor, or other known processing element. Inthe illustrated implementation, processor 1410 acts as a main processingunit and central hub for communication with many of the variouscomponents of the system 1400. As one example, processor 1400 isimplemented as a SoC.

Processor 1410, in one embodiment, communicates with a system memory1415. As an illustrative example, the system memory 1415 is implementedvia multiple memory devices or modules to provide for a given amount ofsystem memory.

To provide for persistent storage of information such as data,applications, one or more operating systems and so forth, a mass storage1420 may also couple to processor 1410. In various embodiments, toenable a thinner and lighter system design as well as to improve systemresponsiveness, this mass storage may be implemented via a SSD or themass storage may primarily be implemented using a hard disk drive (HDD)with a smaller amount of SSD storage to act as a SSD cache to enablenon-volatile storage of context state and other such information duringpower down events so that a fast power up can occur on re-initiation ofsystem activities. Also shown in FIG. 14, a flash device 1422 may becoupled to processor 1410, e.g., via a serial peripheral interface(SPI). This flash device may provide for non-volatile storage of systemsoftware, including a basic input/output software (BIOS) as well asother firmware of the system.

Various input/output (I/O) devices may be present within system 1400.Specifically shown in the embodiment of FIG. 14 is a display 1424 whichmay be a high definition LCD or LED panel that further provides for atouch screen 1425. In one embodiment, display 1424 may be coupled toprocessor 1410 via a display interconnect that can be implemented as ahigh performance graphics interconnect. Touch screen 1425 may be coupledto processor 1410 via another interconnect, which in an embodiment canbe an I²C interconnect. As further shown in FIG. 14, in addition totouch screen 1425, user input by way of touch can also occur via a touchpad 1430 which may be configured within the chassis and may also becoupled to the same I²C interconnect as touch screen 1425.

For perceptual computing and other purposes, various sensors may bepresent within the system and may be coupled to processor 1410 indifferent manners. Certain inertial and environmental sensors may coupleto processor 1410 through a sensor hub 1440, e.g., via an I²Cinterconnect. In the embodiment shown in FIG. 14, these sensors mayinclude an accelerometer 1441, an ambient light sensor (ALS) 1442, acompass 1443 and a gyroscope 1444. Other environmental sensors mayinclude one or more thermal sensors 1446 which in some embodimentscouple to processor 1410 via a system management bus (SMBus) bus.

Also seen in FIG. 14, various peripheral devices may couple to processor1410 via a low pin count (LPC) interconnect. In the embodiment shown,various components can be coupled through an embedded controller 1435.Such components can include a keyboard 1436 (e.g., coupled via a PS2interface), a fan 1437, and a thermal sensor 1439. In some embodiments,touch pad 1430 may also couple to EC 1435 via a PS2 interface. Inaddition, a security processor such as a trusted platform module (TPM)1438 may also couple to processor 1410 via this LPC interconnect.

System 1400 can communicate with external devices in a variety ofmanners, including wirelessly. In the embodiment shown in FIG. 14,various wireless modules, each of which can correspond to a radioconfigured for a particular wireless communication protocol, arepresent. One manner for wireless communication in a short range such asa near field may be via a NFC unit 1445 which may communicate, in oneembodiment with processor 1410 via an SMBus. Note that via this NFC unit1445, devices in close proximity to each other can communicate.

As further seen in FIG. 14, additional wireless units can include othershort range wireless engines including a WLAN unit 1450 and a Bluetoothunit 1452. Using WLAN unit 1450, Wi-Fi™ communications can be realized,while via Bluetooth unit 1452, short range Bluetooth™ communications canoccur. These units may communicate with processor 1410 via a given link.

In addition, wireless wide area communications, e.g., according to acellular or other wireless wide area protocol, can occur via a WWAN unit1456 which in turn may couple to a subscriber identity module (SIM)1457. In addition, to enable receipt and use of location information, aGPS module 1455 may also be present. Note that in the embodiment shownin FIG. 14, WWAN unit 1456 and an integrated capture device such as acamera module 1454 may communicate via a given link.

An integrated camera module 1454 can be incorporated in the lid. Toprovide for audio inputs and outputs, an audio processor can beimplemented via a digital signal processor (DSP) 1460, which may coupleto processor 1410 via a high definition audio (HDA) link. Similarly, DSP1460 may communicate with an integrated coder/decoder (CODEC) andamplifier 1462 that in turn may couple to output speakers 1463 which maybe implemented within the chassis. Similarly, amplifier and CODEC 1462can be coupled to receive audio inputs from a microphone 1465 which inan embodiment can be implemented via dual array microphones (such as adigital microphone array) to provide for high quality audio inputs toenable voice-activated control of various operations within the system.Note also that audio outputs can be provided from amplifier/CODEC 1462to a headphone jack 1464. Although shown with these particularcomponents in the embodiment of FIG. 14, understand the scope of thepresent invention is not limited in this regard.

Embodiments may be implemented in many different system types. Referringnow to FIG. 15, shown is a block diagram of a system in accordance withan embodiment of the present invention. As shown in FIG. 15,multiprocessor system 1500 is a point-to-point interconnect system, andincludes a first processor 1570 and a second processor 1580 coupled viaa point-to-point interconnect 1550. As shown in FIG. 15, each ofprocessors 1570 and 1580 may be multicore processors, including firstand second processor cores (i.e., processor cores 1574 a and 1574 b andprocessor cores 1584 a and 1584 b), although potentially many more coresmay be present in the processors. Each of the processors can include aPCU or other power management logic to perform processor-based powermanagement as described herein.

Still referring to FIG. 15, first processor 1570 further includes amemory controller hub (MCH) 1572 and point-to-point (P-P) interfaces1576 and 1578. Similarly, second processor 1580 includes a MCH 1582 andP-P interfaces 1586 and 1588. As shown in FIG. 15, MCH's 1572 and 1582couple the processors to respective memories, namely a memory 1532 and amemory 1534, which may be portions of system memory (e.g., DRAM) locallyattached to the respective processors. First processor 1570 and secondprocessor 1580 may be coupled to a chipset 1590 via P-P interconnects1562 and 1564, respectively. As shown in FIG. 15, chipset 1590 includesP-P interfaces 1594 and 1598.

Furthermore, chipset 1590 includes an interface 1592 to couple chipset1590 with a high performance graphics engine 1538, by a P-P interconnect1539. In turn, chipset 1590 may be coupled to a first bus 1516 via aninterface 1596. As shown in FIG. 15, various input/output (I/O) devices1514 may be coupled to first bus 1516, along with a bus bridge 1518which couples first bus 1516 to a second bus 1520. Various devices maybe coupled to second bus 1520 including, for example, a keyboard/mouse1522, communication devices 1526 and a data storage unit 1528 such as adisk drive or other mass storage device which may include code 1530, inone embodiment. Further, an audio I/O 1524 may be coupled to second bus1520. Embodiments can be incorporated into other types of systemsincluding mobile devices such as a smart cellular telephone, tabletcomputer, netbook, Ultrabook™, or so forth.

A processor, such as a multi-core processor, may have a power managementunit (PMU) that can monitor telemetry data associated with powerconsumption of portions of the processor, e.g., the cores, one or morecaches, interconnect, uncore, etc. The PMU may adjust power supplied toeach of the components based on the telemetry data received.

For example, the telemetry data may include, for each core of amulti-core processor for a particular time period, an indication (alsomeasurement herein) of an event occurrence or of multiple occurrences ofthe event. That is, for each type of event the telemetry data mayinclude a corresponding value to indicate how many times the event hasoccurred (e.g., single bit value to indicate a single instance of theevent, or a multi-bit value to indicate how many times the event hasoccurred between reports).

Events may include, but are not limited to: streaming single instructionmultiple data instruction multiple data (SIMD) extension instructions(SSE 128, 256, 512 bit), fused multiply/add (FMA) instructions,mid-level cache lookup, data cache load/store dispatch, memoryload/store, instruction decode, micro-operation allocation, branchpredictor thread identification replace, out-of-order (OOO) threadselect, power meter measurement, instances that the core is in an activestate (e.g., C0 power state), instances of the core in a C1 power state,instances of the core in a C6 power state, detection of a current spike,e.g., via comparison of current slope (dI/dt) to a threshold value,energy efficiency count (e.g., a count of instances that misses occurthat result in accesses to a dynamic random access memory (DRAM) due toa backlog at the OOO), and other events that may be measured on aperiodic basis or on a continual basis.

Each measurement may be determined by a local counter. A cumulativecount (also tally herein) for a time period between requests from thePMU may be stored in a corresponding accumulator (also accumulator logicherein).

Accumulators may be placed in the PMU to sum telemetry data that is tobe received over successive periods and to store cumulative telemetrydata, e.g., a sum of the data received over a defined time period. Inorder to maintain low error and low jitter rate of the cumulativetelemetry data, the accumulators in the PMU may read the telemetry dataat frequent intervals. Frequent reads to be received from each componentmay result in transport congestion in a link (e.g., a sideband path)used to transport the data, e.g., via an on-chip system fabric link(OSF).

If the accumulators are to be situated within the PMU, a “push” (e.g.,initiation of transmission) of data by each local counter to thecorresponding accumulator may be implemented. When the accumulators aresituated in the PMU, each push of data from a local counter in the corevia, e.g., a sideband path to a corresponding accumulator may occurafter the corresponding counter measures its parameter value, e.g., eachpush is to occur after each measurement.

In embodiments, the accumulators to store telemetry data for one or morecores (or other elements of the processor) may be placed inside of therespective core (or other element of the processor). Infrastructure forthe processor may include an accumulator per telemetry parameter in thecore. Each accumulator may operate through use of VCC of the core andsingle frequency clock (e.g., a low frequency clock) of the core. Thecore to be monitored by the accumulators may include a power managementagent (PMA), which may be implemented in hardware, software, firmware,or a combination thereof. The PMA may include logic to set operationalparameters such as accumulator update rate (ACC_UPDATA_RATE) based on acorresponding parameter that may be stored into a control register (CR)of the PMA (e.g., by the PMU) and that may specify how often eachaccumulator is to be updated. The accumulator update rate may beselected to minimize jitter. In some embodiments the PMA is to operatein its own power domain that is distinct from the core, e.g., accordingto a different clock (e.g., the PMA may operate at a lower clockfrequency than the core. For example, in one embodiment, the PMA mayoperate with a clock frequency of approximately 100 MHz). Eachaccumulator may store a sum of the telemetry data provided by acorresponding local counter. The local counter may provide the telemetrydata to its accumulator at a high frequency to maintain low jitter andhigh accuracy, while the accumulator may provide the summed data(cumulative telemetry data over an extended time period) to the PMU at alower frequency (e.g., longer time interval between reports to the PMU),which can result in reduced data traffic within the side band path tothe PMU.

In some embodiments, the PMA may include PMA CRs to store thresholds pertelemetry parameter (Tele_Thres). For example, each PMA CR may specify acorresponding parameter threshold. When the accumulator value exceedsthe parameter threshold, the PMA within the core may not wait for a“pull command” (e.g., request for the telemetry data issued by the PMU),but instead the PMA may push, to the PMU, the telemetry data in theaccumulator whose value exceeds the corresponding parameter threshold.Such CRs may enable the PMA to recognize an occurrence of an event or awarning of an impending event associated with a telemetry data valuethat exceeds a corresponding threshold, and to notify the PCU uponrecognition of the event or impending event.

In some embodiments, the PMU may include virtual wire CRs (Tele_Vir_WireCR). If a threshold stored in one of the PMA CRs is exceeded, a value inthe corresponding Tele_Vir_Wire CR may be set and may serve as anotification to the PMU of the corresponding event, which may cause thePMU to adjust one or more operating parameters of one or more of thecores of the processor in order to avoid potential negative consequencesassociated with the event, e.g., overheating, processor malfunction,etc. Additionally, in some embodiments when overflow of an accumulatorhas occurred, a communication may be sent to the PMU.

In embodiments, a GO command (“pull”) may be issued from the PMU totelemetry monitors, e.g., to PMA and accumulators of a particular core.The PMU may issue the GO command to request cumulative telemetry datacollected by the accumulators in the core. When the core receives the GOmessage, a “snapshot” of values of all of the accumulators may be taken,e.g., by the PMA, and sent to the PMU.

In some embodiments, each accumulator is to read data from its core atthe data collection rate specified by Acc_Updata_Rate, e.g., to resultin low jitter and low error. Upon receipt by the PMA of the GO command,the cumulative value in each accumulator may be sent to the PMU to bestored in a control register that corresponds to the core.

In embodiments, when a GO command is received by the PMA from the PMU,each accumulator may provide (e.g., “push”) its contents to the PMU viathe PMA, e.g., when the PMA receives the GO command it takes a snapshotof all the accumulators, to be stored as telemetry data in temporaryregisters. The PMA may send the telemetry data to CRs within the PMU.

In an embodiment, the PMU may have one CR per core. The CR may include afield to carry telemetry identification (ID) information. After thetelemetry data is reported to the PMU, local counters may continue tocollect data to be sent to their respective accumulators. In someembodiments, the accumulators may be reset after the stored data hasbeen reported to the PMU. In other embodiments, one or more accumulatorsmay continue to tally events without a reset of the corresponding valuestored.

In the PMU, responsive to a particular accumulator having reached acritical value, an indicator may be set (e.g., a bit) in theTele_Vir_Wire CR. Responsive to the indicator, the PMU may issue acommand to read the particular accumulator, or the PMU may ignore theindicator.

The PMU may run a “loop” on all cores, e.g., read correspondingtelemetry data from each core, e.g., consecutively. A pull period (pulltime interval) between reads of the cumulative telemetry data from agiven core to the PMU may be, e.g., one millisecond, or greater than onemillisecond. In contrast, the local counters may provide parametervalues to their respective accumulators at a much higher frequency,e.g., the time interval between parameter value measurements by localcounters may be on the order of 10 μsec.

After the GO command is issued, each core is to send a message withtelemetry data collected from all accumulators of the core (e.g.,snapshot). After each core sends its telemetry data, the PMU may receivean acknowledge (ACK) from the core. When all ACKs are in place, the PMUcan begin to analyze the data.

Because the PMU determines when the telemetry data is to be received,the PMU can request data from each core only after a current core isfinished with data collection. As a result, data traffic congestion via,e.g., a sideband route (e.g., OSF sideband) may be avoided without lossof accuracy, since the data is collected by the local counters at arapid rate.

The PMU may call for the telemetry data (e.g., “pull command”) in andmay use the collected telemetry data to determine power-relatedparameters, e.g., voltage to the core, clock frequency of the core,operating voltage and clock frequency of other cores, etc. The pullcommand may be generated on a periodic basis, e.g., after a pull timeinterval (“pull period”) expires, or on an as-needed basis determined bythe PMU.

The pull period in a processor configuration in which accumulatorslocated in a core may exceed a push period of data delivery for aconfiguration in which the accumulators are located in the PMU. That is,with the accumulators in the core, data is to be sent to the PMU lessfrequently than when the accumulators are in the PMU, and consequentlyreduction of traffic congestion in a sideband path may result fromlocation of the accumulators in the cores.

In embodiments in which the accumulators are located in the core, eachcore may additionally include a push mechanism to trigger a push oftelemetry data to the PMU, e.g., when a count in a particularaccumulator exceeds a threshold value. For example, a count of highdI/dt events may exceed a corresponding threshold value and can triggera push of the corresponding telemetry data from a dI/dt eventaccumulator to the PMU, independent of any pull commands that mightotherwise be generated by the PMU. A push of the dI/dt data may enablethe PMU to quickly react to, e.g., an imminent rise of temperature ofthe core due a series of current spikes.

FIG. 16 is a block diagram of a processor in accordance with anembodiment of the present invention. Processor 1600 includes a coreregion 1602, an uncore region 1604, and a sideband path (also channelherein) 1650, e.g., a portion of on-chip system fabric (OSF) that is toconnect the core region 1602 and the uncore region 1604.

The core region 1602 includes a cache memory 1604, interconnect logic1606, a plurality of cores 1612 ₀-1612 _(N) and may include additionalcomponents (not shown).

The uncore region 1604 includes a power management unit (PMU) 1632 thatis to include telemetry data request logic 1634 and telemetry datareception logic 1636, and may include additional components (not shown).The uncore region 1604 may include other components (not shown).

As an exemplary core, core 1612 ₀ includes a plurality of local counters1616 _(i), (i=1 to M) and a corresponding accumulator 1618 _(i) for eachlocal counter 1616 _(i). Contents (e.g., a snapshot of collected data)of each accumulator 1618 _(i) may be provided to a power managementagent (PMA) 1626, e.g., upon request by the PMA 1626.

In operation, each local counter 1616 _(i) may generate an indication(e.g., a count) in response to a particular core event type (e.g. dI/dtspike, memory load, memory store, etc.) and the local counter 1616 _(i)may send the indication to the corresponding accumulator 1618 _(i). Eachaccumulator 1618 _(i) is to store a cumulative sum of indicationsreceived from the corresponding local counter 1616 _(i).

The telemetry data request logic 1634 may generate a pull command to besent to a core 1612 _(i), e.g., via a sideband path 1650. Responsive tothe pull command, the PMA 1626 may retrieve and transmit contents ofeach of the accumulators 1618 _(i) to the telemetry data reception logic1636 via the sideband path 1650. In embodiments, the telemetry datarequest logic 1634 may generate a pull command to each core 1612 _(i)independently, e.g., consecutively, so as to avoid traffic congestion ofdata to be transported via the sideband path 1650 from the PMA 1628 tothe PMU 1632.

The telemetry data reception logic 1636 may receive the telemetry datafrom the accumulators 1618 _(i) via the PMA 1626. Based upon thereceived telemetry data the PMU 1632 may determine whether to causeadjustment of one or more power parameters associated with the coreregion 1602, e.g., core voltage, clock frequency, etc. associated withthe core 1612 ₀. For example, the PMU 1632 may adjust core voltage to beprovided to one or more of the cores 1612 _(i) via an integrated voltageregulator (not shown). Alternatively or additionally, the PMU 1632 maycause an adjustment of a clock frequency of one or more of the cores1612 _(i) via e.g., a PMA of the core 1612 _(i), or may cause anotherpower parameter of one or more cores to be changed responsive toanalysis by the telemetry data reception logic 1636, of the telemetrydata provided by each core 1612 _(i).

FIG. 17 is a block diagram of a processor 1700, according to anotherembodiment of the present invention. The processor 1700 includes a coreregion 1702 that includes a plurality of cores 1712 _(i) (i=1, N), anuncore region 1704 that includes a power management unit (PMU) 1730, anda sideband path 1750 (e.g., a portion of on-chip system fabric (OSF) tocouple the cores 1712 _(i) to the PMU 1730. Other logics and/or storageregisters (not shown) may also be included in the processor 1700.

In operation, one or more of the cores 1712 _(i) may include a pluralityof report logics (e.g., local counters) 1716 _(i) (i=1, M) and acorresponding plurality of accumulator logics 1718 _(i). Each reportlogic 1716 _(i) may provide to the corresponding accumulator logic 1718_(i) during a given time period (e.g., once per each clock cycle), atelemetry value associated with a particular telemetry variable, e.g.,an indication of whether an event has occurred (e.g., load, store, adI/dt spike, floating point operation, etc.) or a count of instances ofthe event occurrence within the given time period. Each accumulatorlogic 1718 _(i) is to maintain a cumulative sum of the telemetry valuesreceived from its respective report logic 1716 _(i) during a pull timeperiod (“pull interval”) between consecutive pull commands to bereceived from the PMU 1730.

Upon receipt by the core 1712 ₀ of a pull command (e.g., via sidebandpath 1750, or via another path) data collection logic 1726 may collect(“take a snapshot” of) the telemetry data in the accumulator logics 1718_(i) (i=1, M). The PMA 1720 may provide the collected telemetry data tothe PMU 1730 via the sideband path 1750 responsive to the pull command.

The PMA 1720 may include threshold control registers 1722 _(i) andcomparison logic 1724 _(i) (i=1, M) for each telemetry data type whoseindications are summed by the corresponding accumulator logic 1718 _(i).The comparison logic 1724 _(i) may compare a current telemetry valuestored in the accumulator 1718 _(i) to a threshold value stored in thecorresponding threshold control register 1722 _(i) and if the currenttelemetry value exceeds the threshold value, the comparison logic 1724_(i) may push the current telemetry value to the PMU 1730 (e.g., via a“virtual wire”) to be stored in trigger value CR 1739, which may warnthe PMU 1730 that the telemetry value has “spiked,” which may correlateto a power spike or imminent power spike. Power adjustment logic 1738 inthe PMU 1730 may respond to the pushed telemetry data, e.g., byadjustment of one or more operating parameters of the core 1712 ₀, e.g.,adjustment of operating voltage, clock frequency, duty cycle, throttlingof throughput, etc.

The PMA 1720 may also include an accumulator update rate controlregister 1729 that may be set, e.g., by the PMU 1730, or by an operatingsystem (not shown), or by another data management source. Theaccumulator update rate control register 1729 may store, e.g., a datacollection rate at which the report logics 1716 _(i) are to providetelemetry values to their respective accumulators 1718 _(i).

The PMA 1720 may also include power adjustment logic 1728 that canadjust one or more operation parameters, e.g., clock frequency of thecore 1712 ₀, based upon input received from the PMU 1730.

The PMU 1730 may include telemetry data request logic 1732 to generatepull commands upon decision by the PMU 1730. The pull commands may begenerated periodically or may be generated aperiodically. The PMU 1730may also include telemetry data reception logic 1734 to store thetelemetry data received from each core into corresponding telemetry datastorage 1736 _(i). Each telemetry data storage 1736 _(i) may include anidentification to identify each particular type of telemetry datareceived from a particular core. Additionally, the PMU 1730 may includetrigger value control registers 1739 to receive an indication that athreshold has been exceeded, as determined in the PMA 1720, e.g., bycomparison logic 1724 _(i). The PMU 1730 may respond to an indicationplaced in the trigger value control registers 1739, or may choose toignore the indication. For example, the PMU 1730 may respond by alertingpower adjustment logic 1738 to issue a command to adjust one or moreoperational parameters of one or more of the cores 1712 _(i).

The power adjustment logic 1738 may analyze the telemetry data stored inthe telemetry data storages 1736 _(i), and may determine whether toadjust one or more operational parameters of the processor 1700, basedat least in part on the values stored in telemetry data storages 1736_(i).

Upon issuance of a pull command and after telemetry data values of aparticular core 1712 i have been reported to the PMU 1730, the telemetrydata values stored in each accumulator logic of the particular core(e.g., accumulator logics 1718 _(i) of core 1712 ₀) may be reset, and anext data collection period may begin.

In processor 1700, the accumulator logics 1718 _(i) are located withineach core 1712 _(i), and the pull time interval between generation ofpull commands may be longer than, e.g., a push time period between datapush events for a system in which all accumulators are located in thePMU 1730. Placement of the accumulators in the core 1712 _(i) may resultin a reduced frequency of transmission of telemetry data from each coreto the PMU 1730, and can reduce congestion in the interconnect 1750without loss of access to the data by the PMU 1730.

After each core 1712 _(i) has sent its telemetry data to the PMU 1730,each core 1712 _(i) also may send an acknowledgment to the PMU 1740 asan indication that the telemetry data has been sent. Whenacknowledgments have been received from all cores 1712 _(i), analysis ofthe received telemetry data can commence.

FIG. 18 is a flow diagram of a method 1800, according to an embodimentof the present invention. At block 1802 a rate of accumulator update isset, e.g., time period between updates of one or more accumulators(e.g., data received from a local counter) of a core of a multi-coreprocessor. For example, the rate of accumulator update may be determinedby a PMU of the processor. Each accumulator is to tally a correspondingtelemetry value of the core in which the accumulator is placed. Eachcore includes the one or more accumulators that tally correspondingtelemetry values of a respective telemetry parameter for that core.

Continuing to block 1804, accumulators are reset at a beginning of apull time period, e.g., after a previous pull command from the PMU hasbeen responded to by providing the accumulator values stored in eachaccumulator of a core.

Advancing to block 1806, each telemetry value may be read by in acorresponding local counter in the core. Moving to block 1808, eachtelemetry value may be added to an accumulated value in thecorresponding accumulator within the core.

Proceeding to block 1810, if the PMU issues a pull command, e.g.,request for telemetry data stored in the accumulators of a particularcore, continuing to block 1814 the accumulator values of the particularcore are sent to the PMU, e.g., via a sideband path, and returning toblock 1804, the accumulators within the core are to be reset. If, atdecision diamond 1810, the PMU has not issued a pull command, continuingto decision block 1812, if an accumulator has overflowed, proceeding toblock 1814 the accumulator values in each of the accumulators within thecore are to be sent to the PMU, and returning to block 1804, theaccumulators within the core are to be reset.

If no accumulator has overflowed, continuing to decision diamond 1816,if none of the accumulators stores an accumulator value that exceeds acorresponding threshold_(i) returning to block 1806 telemetry values areread and stored in respective accumulators at block 1808 periodically atthe accumulator update rate set in block 1802. If, at decision diamond1816, an accumulator value of accumulator_(i) has exceeded itscorresponding threshold_(i), (e.g., determined via a comparisonperformed within a power management agent (PMA)), proceeding to block1818 an indication that accumulator_(i) has exceeded its threshold_(i)is initiated from the core to the PMU. Returning to block 1806 telemetryvalues are read and stored in respective accumulators at block 1808periodically at the accumulator update rate set in block 1802.

In embodiments, each core may receive a respective pull commandindependently. In embodiments, the pull commands are issuedconsecutively, so as to reduce congestion in the sideband path thattransports the accumulator values from each core to the PMU.

FIG. 19 is a flow diagram of a method, according to another embodimentof the present invention. Method 1900 starts at block 1902. Continuingto block 1904, an index i is set equal to zero, and a pull timer in aPMU of a multi-core processor is started to time a pull period, e.g.,time interval between issuance of pull commands. Advancing to decisiondiamond 1906, if an indication of overflow of an accumulator within acore of the processor is received at a PMU of the processor, moving toblock 1908 the PMU is to request telemetry data from the core and inresponse the PMU is to receive the telemetry data of the accumulators inthe core. A PMA within the core is to reset the accumulators after thetelemetry data has been transmitted to the PMU.

Proceeding to block 1910, if an accumulator value of a core exceeds athreshold (as determined by the PMA of the core), continuing to block1912 the PMU is to receive an indication that the threshold has beenexceeded, and/or the accumulated telemetry data pushed from the PMA ofthe core. Advancing to block 1914, the PMU is to determine whether totake an action, e.g., power management action, based on based ontelemetry data received and/or based on the indication the threshold hasbeen exceeded. For example, an indication that the accumulator valueexceeds the corresponding threshold may indicate that a thermalcondition is imminent, and the PMU may determine to reduce activitylevel of the core, e.g., via reduction of instruction throughput (e.g.,throttling), reduction of clock speed, reduction of operating voltage,etc. or a combination thereof.

Moving to block 1916, if the pull period is not expired, the PMU waitsuntil the pull period is expired. Upon expiry of the pull period,proceeding to block 1918 the index is incremented, and continuing toblock 1920 a pull command is issued to an i^(th) core of the processor.Proceeding to block 1922, telemetry data is received from the i^(th)core responsive to the pull command and the received telemetry data isstored in an i^(th) control register (CR) corresponding to the i^(th)core, within the PMU.

Continuing to decision diamond 1924, if i has not reached a value N thatcorresponds to all cores having been issued a respective pull command(e.g., the processor includes a total of N cores), returning to block1918, the index i is incremented and a next pull command is issued tothe i^(th) core. If at decision diamond i=N, advancing to block 1926,the PMU is to determine whether to change any operating parameter(s) ofeach core based on the received telemetry data. Changes may includeadjustment of any of operating voltage (Vcc), clock frequency, dutycycle, throttling, etc. and combinations thereof.

Moving to block 1928, the pull period timer is reset, and returning toblock 1904 the method is repeated. Within each core, the accumulatorsmay be reset prior to a start of each pull period, e.g., start of thepull timer.

Thus, in embodiments, the PMU is to control when telemetry data isreceived via issuance of pull commands. Within each core, telemetry datamay be collected and tallied at a high data collection rate byaccumulators in the core and may subsequently be received by the PMU ata data reception rate, e.g., lower than the data collection rate, thedata reception rate determined at least in part by the pull period. Alow data reception rate may result in reduced data transport congestionfrom the cores to the PMU via a sideband path.

Additional embodiments are described below.

In a first embodiment, a processor includes a plurality of coresincluding a first core. The first core includes a first plurality ofaccumulator logics, each accumulator logic of the first plurality ofaccumulator logics to store respective first core telemetry data. Thefirst core also includes a power management unit (PMU) to request firstcore telemetry data from the first core and in response to receive atleast one first core telemetry data stored in a correspondingaccumulator logic of the first plurality of accumulator logics.

A second embodiment includes elements of the 1^(st) embodiment, where asecond core of the plurality of cores includes a second plurality ofaccumulator logics, each accumulator logic of the second plurality ofaccumulator logics to store respective second core telemetry data thatincludes a sum of values of a corresponding second core telemetryparameter, and where the PMU is to request second core telemetry datafrom the second core and in response is to receive at least one secondcore telemetry data stored in a corresponding accumulator logic of thesecond plurality of accumulator logics.

A 3^(rd) embodiment includes elements of the 2^(nd) embodiment.Additionally, subsequent to receipt of the at least one first coretelemetry data of the first core the PMU is to request the second coretelemetry data and receive the at least one second core telemetry datafrom the second core.

A 4^(th) embodiment includes elements of the 1^(st) embodiment.Additionally, the first core includes a power management agent (PMA) anda control storage corresponding to a first accumulator logic of thefirst core, the control storage to store a threshold value. The PMA isto determine whether the first core telemetry data stored in the firstaccumulator logic exceeds the threshold value stored in the controlstorage and if so, to notify the PMU.

A 5^(th) embodiment includes elements of the 1^(st) embodiment.Additionally, the first core telemetry data stored in a firstaccumulator logic corresponds to an accrued count of instances that thefirst core has been in a reduced activity state during a first timeperiod.

A 6^(th) embodiment includes elements of the 1^(st) embodiment, furthercomprising a sideband path to couple the first core and the PMU, whereinthe at least one first core telemetry data is to be received by the PMUvia the sideband path.

A 7^(th) embodiment includes elements of any one of the 1^(st) to the6^(th) embodiments, where the PMU is to determine, based at least inpart on the first core telemetry data received, at least one of anoperating voltage and a clock frequency at which to operate the firstcore.

An 8^(th) embodiment includes elements of any one of the 1^(st) to the6^(th) embodiments. The processor of any one of claims 1 to 6, whereinthe first core includes a power management agent (PMA) to notify the PMUwhen a particular accumulator logic of the first plurality ofaccumulator logics is in an overflow condition.

A 9^(th) embodiment is a processor that includes a plurality of coresincluding a first core that includes first accumulator logic to count,at a first data collection rate, first telemetry data associated withthe first core. The processor also includes a power management unit(PMU) to periodically issue a first core request to the first core at arequest rate, and responsive to the first core request, to receive thefirst telemetry data stored in the first accumulator logic, wherein thefirst data collection rate is to exceed the request rate.

A 10^(th) embodiment includes elements of the 9^(th) embodiment. Theplurality of cores includes a second core that includes a secondaccumulator logic to store second telemetry data associated with thesecond core, where responsive to a second core request issued by the PMUto the second core, the PMU is to receive the second telemetry datastored in the second accumulator logic.

An 11^(th) embodiment includes elements of the 10^(th) embodiment.Additionally, the first telemetry data and the second telemetry data areto be received consecutively by the PMU via a sideband path responsiveto consecutive issuance of the first core request and the second corerequest.

A 12^(th) embodiment includes elements of the 9^(th) embodiment.

Additionally, the first core includes a first control register to storea threshold value, and the first core includes a first power managementagent (PMA) to notify the PMU when the first telemetry data exceeds thethreshold value.

A 13^(th) embodiment includes elements of the 9^(th) embodiment, wherefirst telemetry data corresponds to a count of instances that the firstcore has been in a reduced activity state during a time period betweenthe issuance of successive first core requests.

A 14^(th) embodiment includes elements of the 9^(th) embodiment. Firsttelemetry data corresponds to a count of instances that a rate ofcurrent flow (dI/dt) in the first core exceeds a first threshold duringa time period between issuance of successive first core requests.

A 15^(th) embodiment includes elements of the 9^(th) embodiment, wherethe first core includes a power management agent (PMA), and whereresponsive to the first accumulator logic being in an overflow conditionthe PMA is to send an overflow indicator to the PMU.

A 16^(th) embodiment includes elements of the any one of the 9^(th) tothe 15^(th) embodiments, where responsive to receipt of the firsttelemetry data, the PMU is to determine whether to adjust a power usageparameter associated with the first core.

A 17^(th) embodiment includes elements of any one of the 9^(th) to the15^(th) embodiments, and further includes a sideband path, wherein thefirst telemetry data is to be received by the PMU via the sideband path.

An 18^(th) embodiment is a machine-readable medium having stored thereondata, which if used by at least one machine, cause the at least onemachine to fabricate at least one integrated circuit to perform a methodthat includes storing in a first core of a processor a plurality offirst core cumulative telemetry values, where each first core cumulativetelemetry value is to be stored in a corresponding accumulator logic,and where each first core cumulative telemetry value includes a sum ofvalues of a corresponding first core telemetry parameter measured over asummation time period. The method further includes responsive to a firstcore first request to be received by the first core from a powermanagement unit (PMU) of the processor upon expiry of the summation timeperiod, sending from the first core to the PMU first core telemetryinformation corresponding to at least one of the first core cumulativetelemetry values.

A 19^(th) embodiment includes elements of the 18^(th) embodiment, wherethe sum of values of a particular first core telemetry parameter is tobe determined from at least two values measured during the summationtime period.

A 20^(th) embodiment includes elements of the 18^(th) embodiment, wherethe method further includes storing in a second core of the processor aplurality of second core cumulative telemetry values, where each secondcore cumulative telemetry value is to be stored in a correspondingaccumulator logic, where each second core cumulative telemetry valueincludes a sum of values of a corresponding second core telemetryparameter measured over the summation time period. The method includesresponsive to a second core first request to be received by the secondcore from the PMU upon expiry of the summation time period, sending fromthe second core to the PMU second core telemetry informationcorresponding to at least one of the second core cumulative telemetryvalues.

A 21^(th) embodiment includes elements of the 18^(th) embodiment. Themethod further includes notifying the PMU when one of the first corecumulative telemetry values exceeds a threshold value.

A 22^(th) embodiment includes elements of any one of the 18^(th) to the21^(st) embodiment. The method further includes sending the first coretelemetry information from the first core to the PMU via a sideband pathof the processor.

A 23^(rd) embodiment is a method that includes storing in a first coreof a processor a plurality of cumulative telemetry values, wherein eachcumulative telemetry value is to be stored in a correspondingaccumulator logic, wherein each cumulative telemetry value includes asum of values of a corresponding telemetry parameter measured over asummation time period. The method further includes responsive to arequest received by the first core from a power management unit (PMU) ofthe processor upon expiry of the summation time period, sending from thefirst core to the PMU telemetry information corresponding to at leastone of the cumulative telemetry values.

A 24^(th) embodiment includes elements of the 23^(rd) embodiment, wherethe sum of values is to be determined from at least two successivevalues measured during the time period.

A 25^(th) embodiment includes elements of the 23^(rd) embodiment, andfurther includes notifying the PMU when one of the cumulative telemetryvalues exceeds a threshold value.

A 26^(th) embodiment includes elements of any one of embodiments 23 to25, and further includes sending the first core telemetry informationfrom the first core to the PMU via a sideband path of the processor.

A 27^(th) embodiment includes apparatus that includes means forperforming the method of any one of embodiments 23-25.

A 28^(th) embodiment is a method that includes determining by a powermanagement unit (PMU) of a processor that a pull time period haselapsed, the pull time period to begin at a start time, and in response,issuing a first core pull command to a first core of the processor. Themethod also includes responsive to issuing the first core pull command,receiving at the PMU from the first core first core telemetryinformation that includes a first core cumulative telemetry value, wherethe first core cumulative telemetry value corresponds to a summation ofa plurality of measurements of a telemetry parameter of the first core,wherein each measurement is to be measured at a corresponding distincttime during the pull time period.

A 29^(th) embodiment includes elements of the 28^(th) embodiment, andfurther includes receiving the first core telemetry information at thePMU from the first core via a sideband path of the processor.

A 30^(th) embodiment includes elements of the 29^(th) embodiment,further comprising after issuing the first core pull command, issuing asecond core pull command to a second core of the processor and inresponse receiving at the PMU from the second core, second coretelemetry information that includes a second core cumulative telemetryvalue, wherein the second core cumulative telemetry value corresponds toa summation of a plurality of measurements of a telemetry parameter ofthe second core, wherein each measurement is to be measured at acorresponding distinct time during the pull time period.

A 31^(st) embodiment includes the method of any one of embodiments 28 to30, and further includes determining whether to change at least oneoperating parameter of the first core based at least in part on thefirst core cumulative telemetry value.

A 32^(nd) embodiment is an apparatus that includes means for performingthe method of any one of embodiments 28 to 30.

Embodiments may be used in many different types of systems. For example,in one embodiment a communication device can be arranged to perform thevarious methods and techniques described herein. Of course, the scope ofthe present invention is not limited to a communication device, andinstead other embodiments can be directed to other types of apparatusfor processing instructions, or one or more machine readable mediaincluding instructions that in response to being executed on a computingdevice, cause the device to carry out one or more of the methods andtechniques described herein.

Embodiments may be implemented in code and may be stored on anon-transitory storage medium having stored thereon instructions whichcan be used to program a system to perform the instructions. Embodimentsalso may be implemented in data and may be stored on a non-transitorystorage medium, which if used by at least one machine, causes the atleast one machine to fabricate at least one integrated circuit toperform one or more operations. The storage medium may include, but isnot limited to, any type of disk including floppy disks, optical disks,solid state drives (SSDs), compact disk read-only memories (CD-ROMs),compact disk rewritables (CD-RWs), and magneto-optical disks,semiconductor devices such as read-only memories (ROMs), random accessmemories (RAMs) such as dynamic random access memories (DRAMs), staticrandom access memories (SRAMs), erasable programmable read-only memories(EPROMs), flash memories, electrically erasable programmable read-onlymemories (EEPROMs), magnetic or optical cards, or any other type ofmedia suitable for storing electronic instructions.

While the present invention has been described with respect to a limitednumber of embodiments, those skilled in the art will appreciate numerousmodifications and variations therefrom. It is intended that the appendedclaims cover all such modifications and variations as fall within thetrue spirit and scope of this present invention.

What is claimed is:
 1. A processor comprising: a plurality of coresincluding a first core, wherein the first core includes a firstplurality of accumulator logics, each accumulator logic of the firstplurality of accumulator logics to store corresponding first coretelemetry data; and a power management unit (PMU) to request first coretelemetry data from the first core and in response to the request forthe first core telemetry data to receive at least one first coretelemetry data stored in a corresponding accumulator logic of the firstplurality of accumulator logics.
 2. The processor of claim 1, wherein asecond core of the plurality of cores includes a second plurality ofaccumulator logics, each accumulator logic of the second plurality ofaccumulator logics to store corresponding second core telemetry datacomprising a sum of values of a corresponding second core telemetryparameter, and wherein the PMU is to request second core telemetry datafrom the second core and in response to the request for the second coretelemetry data is to receive at least one second core telemetry datastored in a corresponding accumulator logic of the second plurality ofaccumulator logics.
 3. The processor of claim 2, wherein subsequent toreceipt of the at least one first core telemetry data of the first corethe PMU is to request the second core telemetry data and receive the atleast one second core telemetry data from the second core, to reducetraffic on a sideband interconnect.
 4. The processor of claim 1, whereinthe first core includes a power management agent (PMA) and a controlstorage corresponding to a first accumulator logic of the first core,the control storage to store a threshold value, and wherein the PMA isto determine whether the first core telemetry data stored in the firstaccumulator logic exceeds the threshold value stored in the controlstorage and if so, to notify the PMU.
 5. The processor of claim 1,wherein the first core telemetry data stored in a first accumulatorlogic corresponds to an accrued count of instances that the first corehas been in a reduced activity state during a first time period.
 6. Theprocessor of claim 1, further comprising a sideband path to couple thefirst core and the PMU, wherein the at least one first core telemetrydata is to be received by the PMU via the sideband path.
 7. Theprocessor of claim 1, wherein the PMU is to determine, based at least inpart on the at least one first core telemetry data received, at leastone of an operating voltage and a clock frequency at which to operatethe first core.
 8. The processor of claim 1, wherein the first coreincludes a power management agent (PMA) to notify the PMU when a firstaccumulator logic of the first plurality of accumulator logics is in anoverflow condition, the PMA to operate in a separate power domain than apower domain of the first core.
 9. A processor comprising: a pluralityof cores including a first core that includes first accumulator logic tocount, at a first data collection rate, first telemetry data associatedwith the first core; and a power management unit (PMU) to periodicallyissue a first core request to the first core at a request rate, andresponsive to the first core request, to receive the first telemetrydata stored in the first accumulator logic, wherein the first datacollection rate is to exceed the request rate.
 10. The processor ofclaim 9, wherein the plurality of cores includes a second core thatincludes second accumulator logic to store second telemetry dataassociated with the second core, wherein responsive to a second corerequest issued by the PMU to the second core, the PMU is to receive thesecond telemetry data stored in the second accumulator logic.
 11. Theprocessor of claim 10, wherein the first telemetry data and the secondtelemetry data are to be received consecutively by the PMU via asideband path responsive to consecutive issuance of the first corerequest and the second core request.
 12. The processor of claim 9,wherein the first core includes a first control register to store athreshold value, and wherein the first core includes a first powermanagement agent (PMA) to notify the PMU when the first telemetry dataexceeds the threshold value.
 13. The processor of claim 9, wherein thefirst telemetry data corresponds to a count of instances that the firstcore has been in a reduced activity state during a time period betweenissuance of successive first core requests.
 14. The processor of claim9, wherein the first telemetry data corresponds to a count of instancesthat a rate of current flow (dI/dt) in the first core exceeds a firstthreshold during a time period between issuance of successive first corerequests.
 15. The processor of claim 9, wherein the first core includesa power management agent (PMA), wherein responsive to the firstaccumulator logic being in an overflow condition the PMA is to send anoverflow indicator to the PMU.
 16. The processor of claim 9, whereinresponsive to receipt of the first telemetry data, the PMU is todetermine whether to adjust a power usage parameter associated with thefirst core.
 17. The processor of claim 9, further comprising a sidebandpath, wherein the first telemetry data is to be received by the PMU viathe sideband path.
 18. A non-transitory machine-readable medium havingstored thereon data, which if used by at least one machine, cause the atleast one machine to fabricate at least one integrated circuit toperform a method comprising: storing in a first core of a processor aplurality of cumulative telemetry values, wherein each cumulativetelemetry value is to be stored in a corresponding accumulator logic,wherein each cumulative telemetry value includes a sum of values of acorresponding telemetry parameter measured over a summation time period;responsive to a request to be received by the first core from a powermanagement unit (PMU) of the processor upon expiry of the summation timeperiod, sending from the first core to the PMU telemetry informationcorresponding to at least one of the cumulative telemetry values. 19.The non-transitory machine-readable medium of claim 18, wherein the sumof values is to be determined from at least two values measured duringthe summation time period.
 20. The non-transitory machine-readablemedium of claim 18, wherein the method further comprises sending thetelemetry information from the first core to the PMU via a sideband pathof the processor.